Winit version 0.31.0-beta.4

Added

• Add ActiveEventLoop::clipboard and ActiveEventLoop::set_clipboard for
  interacting with the system clipboard through the data transfer API,
  implemented on Wayland, X11, macOS and Windows.
• Add ActiveEventLoop::primary_selection_ext for interacting with
  the primary selection through the data transfer API on Wayland and X11.
• Add WindowEvent::MouseWheel::source: ScrollSource, telling a mouse wheel
  from fingers on a touchpad from system-driven momentum scrolling, implemented
  on macOS and Wayland.
• Add keyboard support for OpenHarmony.

Fixed

• On Windows, fix a crash occurring when trying to create a DXGI surface on a window that is both fullscreen and always on top.
• On Wayland, use the touch serial for Window::drag_window, Window::drag_resize_window and Window::show_window_menu when the interaction was started by touch.
• On Windows, fix a crash when moving a window that owns windows not created by winit, such as native dialogs or application helper windows.
• On Windows, avoid overflow when negating minimum mouse-wheel deltas.
• On Windows, fix the transparency mask of icons created from RGBA data. Places that
  draw icons through the mask, such as Task Manager, showed a background and rough edges.
• On Windows, fix IME preedit cursor offsets around surrogate pairs when no
  target clause is selected.
• On X11, reset the drag and drop state when a drag operation ends. A later drag no longer reuses the state of a previous drag.
• On Wayland, fix the text input being destroyed whenever a seat capability changed. This made IME input stop working in already-running applications after the seat's capabilities were updated.
• On Wayland, fix a panic when a popup is dropped before its queued compositor
  updates are processed.
• On macOS, forward mouse click events to AppKit. This makes IME semantics more similar to native macOS applications, particularly when an IME is clicked out of.
• On macOS, discard the input method's marked text when IME is disabled, so an unfinished composition is not resumed (and committed again) when IME is re-enabled.

Changed

• No longer send an empty Ime::Preedit before Ime::Commit.
• Removed the url dependency from winit-core, along with SendData::from_file_paths,
  TypedData::try_as_file_paths and impl From<Vec<url::Url>> for SendData. Use SendData::Uris
  / TypedData::try_as_uris with file: URIs instead.